Outdoor decks have become increasingly popular in residential home construction. Homes and apartments, as well as a variety of other buildings, often incorporate exterior decks into their design. Additionally, decks are commonly added onto existing structures. These decks provide convenient space for a variety of outdoor activities, including cookouts, dining and sunbathing, as well as other leisure activities. Exterior decks typically include a floor space fabricated from a number of decking planks, and an underlying support structure including posts, beams and joists.
Wood products have traditionally been the primary source of materials for use in decking construction. However, wood products are becoming increasingly scarce due to the harvesting of trees at ever faster rates and the rather limited rate at which timber resources can be replenished. Also, environmental concerns and environmental relations directed to conservation or preservation of forests tend to restrict the availability of wood products. With diminishing availability of timber resources, wood products are becoming increasingly expensive. There is, therefore, a substantial need for long-lasting substitute construction materials that can lessen the need to harvest timber resources.
It has been found that one potential approach to addressing the above need is to provide substitute replacement decking products made of plastic, rather than wood. Because the deck surface must support substantial weight and foot traffic, however, the replacement products need to be stable and rigid. The material should also be capable of economical manufacture, and be relatively expensive. It also needs to be easily fabricated and used in the field.
A variety of plastic building products are known. For example, U.S. Pat. No. 4,045,603 describes a three-layer synthetic construction material made from recycled waste thermoplastic synthetic resin material and cellulose fiber aggregate. This material includes face surfaces consisting essentially of re-hardened fused and rolled thermoplastic synthetic resin material bits, and an intervening core material consisting essentially of a compressed non-homogenous mixture of cellulose aggregate material bits and re-hardened fused thermoplastic synthetic resin material bits.
U.S. Pat. No. 3,764,245 describes an apparatus for producing light structural board of thermoplastic resin.
U.S. Pat. No. 5,253,458 describes a simulated log made from a cast polyvinylchloride (PVC) pipe, selectively filled with a hard cast foam or a bead type foam. This patent further describes that the cast PVC pipe is first manufactured and then subsequently filled with the foam filler.
These and other known synthetic building products, and methods for their production, tend to require excessive numbers of manufacturing operations at substantial cost. Additionally, known methods for manufacturing foam-filled extruded building products often result in uneven distribution of the foam within the interior of the extruded product, or insufficient bonding between the extruded shell and the foam core, resulting in products having insufficient strength and rigidity for application as a deck material.
The present invention is also directed to a novel attachment system for attaching foam filled extruded plastic decking planks to the deck's underlying support structure. Typical deck construction includes: (1) a number of vertical posts which support the remaining structure above the ground; (2) horizontal beams supported above the ground by the vertical posts; (3) a number of horizontal joists, parallel to and uniformly spaced apart from one another and anchored to the beams; and (4) a floor surface of decking planks arranged horizontally and perpendicular to the joists.
Traditionally, the decking planks have been wooden components of standard dimension, commonly 2.times.6 lumber. The traditional manner of attaching the decking planks to the underlying joists is by nailing or screwing through the plank into the joist below. Although this attachment method may be adequate for standard all-wood deck constructions, it does present a number of disadvantages. For example, nail or screw heads exposed on the top surface of the decking planks are not only aesthetically unappealing, but may present tripping hazards as well. This risk is enhanced over time, as the nails may be pried upwards away from the joists by flexing of the deck planks caused by repeated foot traffic. Additionally, the use of nails or screws necessarily creates holes in the decking planks which may cause the wood to split, and which may accelerate deterioration of the plank caused by weather or insects. Further disadvantages include increased difficulty of cleaning and/or painting the decking planks.
If the joists and the decking are fabricated from different materials of construction, the decking planks and the underlying joists may expand or contract at differing rates due to ambient temperature and humidity fluctuations. Such differences in rates of expansion and contraction can result in unacceptably uneven spacing, stress build-up within the construction components, cracking or buckling.
Accordingly, it can be seen that there is yet a need in the art for foam-filled extruded plastic decking components as a replacement for traditional wood products, which provide a strong finished deck at minimal cost, which resist wear from foot traffic, and which can be produced with a minimal number of manufacturing steps. It is to the provision of such decking components that the present invention is directed.
Accordingly, it can also be seen that a need yet exists for a decking attachment system which securely anchors the decking planks to the support structure while allowing for relative movement between plank and structure in the lengthwise direction of the plank. It is to the provision of such a decking attachment system that the present invention is also directed.